مقاله انگلیسی رایگان در مورد حافظه بررسی شده با تحریک مغز الکتریکی – الزویر 2017

In 1934, Penfield reported that the application of low intensity electrical brain stimulation (EBS) on specific portions of the cortex of an epileptic patient undergoing awake neurosurgery made him/her relive an event of his/her past. Between the 30s and 60s, Penfield reported 40 epileptic patients who experienced psychic phenomena after application of EBS on the neocortex (Penfield, 1958; Penfield and Perot, 1963). Among them, several patients reported reminiscences of past experiences. Penfield assimilated these responses to the dreamy-state occurring spontaneously during seizures described half a century earlier by Hughlings Jackson (1880; 1898). Penfield considered that EBS were reactivating complete stored memory traces, these experiential phenomena being viewed as replays of engrams, like a “tape-recording”: “Past experience, when it is recalled electrically, seems to be complete including all the things of which an individual was aware at the time […]” (Penfield and Perot, 1963). Since Penfield’s pioneering work, several studies have also reported experiential phenomena after EBS (see below for a complete list). However, some of them challenged Penfield’s theory. For example, Gloor (1990) proposed the matrix theory, a reconstructive process whereby EBS leads to the elaboration of excitation and inhibition patterns in widely distributed neural networks, of which some are able to represent a given previous experience, albeit in a caricatured way. Hence, whereas Penfield thought that EBS could induce reminiscence exactly similar to the original event, a bit like playing a videotape at random, Gloor was of the view that only the gist of these memories could be activated. Penfield’s hypothesis remains influential nowadays (Loftus and Loftus, 1980; Simon and Chabris, 2011). But although attractive, whether this conception of a highly stable memory is plausible or whether it is one of the numerous neuromyths that have been identified remains to be clarified (Lilienfeld et al., 2009; Dekker et al., 2012). This situation is largely due to the fact that it is unknown what type of memory EBS can exactly induce. Furthermore, divergent views can be found in the literature about the influence of the localisation of EBS (Penfield, 1958; Halgren et al., 1978; Vignal et al., 2007; Bartolomei et al., 2004). For example, some authors consider that the site of stimulation has no consequence on the type of memory induced, favouring the idea that what matters is the patients’ personality (Halgren et al., 1978; Chauvel, 2006), whereas others suggest that stimulation of specific sites could induce specific types of memories (Bartolomei et al., 2004; Barbeau et al., 2005). However, these reminiscences are nowadays the major source of inspiration for preliminary trials aiming at improving memory performances using EBS (Lee et al., 2013; Suthana and Fried, 2014).